The prior art of the processing of sound allows for the addition to the presentation of a scene, in particular in 3D on a screen, of a spatialized sound in such a way as to improve significantly for the viewer the realism and the sense of immersion in the scene. This technique is appropriate for processing in real time of a limited number of sound sources in the scene.
Scenes, in particular virtual scenes, are becoming more and more complex; in other words, the number of sound sources in a scene is increasing. Accordingly, processing these numerous sound sources in real time, and producing a spatialized sound output for this large number of sound sources is often impossible because of the high cost of processing the signal.
The invention seeks to improve the situation.
The invention relates to a computer device comprising a memory unit capable of storing audio signals, in part pre-recorded, each corresponding to a source defined by the spatial position data, and a processing module for processing these audio signals in real time as a function of the spatial position data.
According to a principal characteristic of the invention, the processing module is capable of calculating the parameters of the instantaneous power level on the basis of the audio signals, the corresponding sources being defined by the said instantaneous power level parameters, the processing module comprising a selection module capable of regrouping a certain number of the audio signals in a variable number of audio signal groups, and the processing module is capable of calculating the representative spatial position data of a group of audio signals as a function of the spatial position data and the parameters of the instantaneous power levels from each corresponding source.
The computer device according to the invention may comprise a large number of additional characteristics, which can be taken separately and/or in combination:                The selection module is capable, prior to the formation of the groups of audio signals, of selecting the inaudible audio signals as a function of the parameters of the instantaneous power levels, comprising a power level and a masking threshold for each source, and of preserving only the audible audio signals;        The power level parameters are calculated for each source on the basis of the spectral density of the instantaneous power, calculated beforehand on the basis of the audio signals in part pre-recorded;        The processing module is capable of processing each group of audio signals into one pre-mixing audio signal and of reassembling the pre-mixing audio signals in order to obtain one mixing signal which is audible to the listener;        The processing module comprises a video processor which is capable of transforming the group of audio signals into a group of textured video signals, of processing each textured video signal from the group according to the sound modification parameters, and of reassembling and transforming the signals into one pre-mixing audio signal;        The modification parameters of the sound comprise one sound attenuation parameter and/or one sound propagation delay parameter;        The selection module is capable of forming, on the basis of a first group of audio signals and calculated data relating to the spatial position of the group, two groups of audio signals, and of calculating the spatial position data of a representative from each of these two groups;        The selection module is capable of determining, on the basis of the first group of audio signals, their corresponding sources, and the calculated data for the spatial position of the representative of the first group, a source for which the sum of the calculated error distances between the spatial position of this source, and those of other sources from the group, is minimal, and is capable of attributing the audio signals of the first group and their corresponding sources to one of the spatial positions among the calculated data for the spatial position of the representative of the first group and the spatial position data of the determined source, as a function of the evaluations of the error distance, in such a way as to form two groups;        The selection module is capable of carrying out an error distance evaluation for an audio signal of the first group and its corresponding source, consisting of evaluating, on the one hand, a part of the error distance between the spatial position data of this source and the calculated spatial position data of the representative of the first group and, on the other, the error distance between the spatial position data of this source and the spatial position data of the determined source, then of evaluating the minimum error distance between the two, and the selection module being capable of attributing the audio signal and its corresponding source to the spatial position data of the determined source or of the representative of the first group corresponding to the minimum distance error;        The spatial position data of the determined source corresponds to the spatial position data of the representative of a second group;        The selection module is capable of calculating the spatial position data of each representative of the group as a function of the power level parameters of each source attributed to the group;        The selection module is capable of recalculating the spatial position data of the representative of each of the two groups, by determining a source for which the sum of the error distances between the spatial position of this source and those of the other sources of the group is minimum, and the selection module is also capable of re-attributing the sources to one or another of the representatives of one of the two groups as a function of the said evaluation of the minimum error distance;        The selection module is capable of recalculating the spatial position data of the representative of each of the two groups, and of re-attributing the sources to one or another of the representatives of one of the two groups until the sum of the error distances between the representatives of the two groups and their sources reaches a minimum;        The selection module is capable of dividing a group until a predetermined number of groups is obtained or until the sum of the error distances between the representatives of the groups and their sources reach a predetermined threshold.        
The invention likewise relates to a method of processing audio signals in part pre-recorded, each corresponding to one source, comprising the stages consisting of:    a. Calculating the instantaneous power level parameters on the basis of audio signals, the corresponding sources being defined by these parameters and by the spatial position data;    b. Regrouping certain of the audio signals into a variable number of audio signal groups and calculating the spatial position data representative of each group of audio signals as a function of the spatial position data and the instantaneous power level parameters of each corresponding source;    c. Processing these audio signals per group, in real time, as a function of the spatial position data representative of the group.
Other characteristics and advantages of the invention can be derived from an examination of the detailed description hereinafter, as well as from the appended drawings.
Appendix 1 shows the mathematical formulae used for the realisation of the invention. Appendix 2 shows the different variables used and their significance.
The drawings and appendices essentially contain the key elements. They can therefore serve not only to provide a better understanding of the description, but also contribute to the definition of the invention, as applicable.